WO2022065799A1

WO2022065799A1 - Media file processing method and apparatus therefor

Info

Publication number: WO2022065799A1
Application number: PCT/KR2021/012664
Authority: WO
Inventors: 헨드리헨드리
Original assignee: 엘지전자 주식회사
Priority date: 2020-09-22
Filing date: 2021-09-16
Publication date: 2022-03-31
Also published as: CN116210223A; US20230345028A1; CN116210223B

Abstract

A media file generation method according to the present document comprises the steps of: configuring first flag information about a target layer in an OLS, the first flag information indicating information about whether the maximum number of temporal sub-layers for inter-layer prediction exists; configuring second flag information about whether the target layer is an output layer; configuring the information about the maximum number of temporal sub-layers on the basis of the first flag information and the second flag information; and generating a media file including an operating point information sample group, wherein the information about the maximum number of temporal sub-layers is configured in the operating point information sample group on the basis of the first flag information being the same as 1 and the second flag information being the same as 0.

Description

Media file processing method and device therefor

This document relates to image coding technology, and more particularly, to a method and apparatus for processing a media file for coded image information in an image coding system.

Recently, the demand for high-resolution and high-quality images such as HD (High Definition) images and UHD (Ultra High Definition) images is increasing in various fields. As the image data becomes high-resolution and high-quality, the amount of information or bits transmitted relatively increases compared to the existing image data. In the case of storage, the transmission cost and the storage cost are increased.

Accordingly, high-efficiency image compression technology is required to effectively transmit, store, and reproduce high-resolution and high-quality image information.

An object of the present document is to provide a method and an apparatus for increasing image coding efficiency.

Another technical problem of the present document is to provide a method and an apparatus for generating a media file for coded image information.

Another technical object of the present document is to provide a method and apparatus for generating a media file for coded image information and metadata of the image information.

According to an embodiment of the present document, there is provided a method for generating a media file performed by an apparatus for generating a media file. The method configures first flag information for a target layer in an output layer set (OLS), wherein the first flag information indicates whether information on the maximum number of temporal sub-layers for inter-layer prediction exists. Step, configuring second flag information on whether the target layer is an output layer, configuring the information on the maximum number of temporal sub-layers based on the first flag information and the second flag information and generating a media file comprising an actuation point information sample group, wherein the actuation point information sample group comprises the first flag information and the second flag information, and wherein the maximum number of the temporal sub-layers The information on is configured in the operation point information sample group based on the first flag information equal to 1 and the second flag information equal to 0.

According to another embodiment of the present document, an apparatus for generating a media file is provided. The media file generating apparatus configures first flag information for a target layer in an output layer set (OLS), wherein the first flag information determines whether information on the maximum number of temporal sub-layers for inter-layer prediction exists indicates whether the target layer is an output layer, configures second flag information on whether the target layer is an output layer, and configures the information on the maximum number of temporal sublayers based on the first flag information and the second flag information and a media file generator for generating a media file including an image processing unit and an operation point information sample group, wherein the operation point information sample group includes the first flag information and the second flag information, and the temporal sublayer The information about the maximum number of is configured in the operation point information sample group based on the first flag information equal to 1 and the second flag information equal to 0.

According to another embodiment of the present document, there is provided a media file processing method performed by a media file processing apparatus. The method includes obtaining a media file including an actuation point information sample group and parsing the actuation point information sample group, wherein parsing the actuation point information sample group comprises: an Output Layer Set (OLS); OLS) parsing the first flag information on the target layer, wherein the first flag information indicates whether information on the maximum number of temporal sub-layers for inter-layer prediction exists, whether the target layer is an output layer Parsing second flag information on whether or not and parsing the information on the maximum number of the temporal sub-layers based on the first flag information and the second flag information, wherein the operation point information A sample group includes the first flag information and the second flag information, and the information about the maximum number of the temporal sub-layers is based on the first flag information equal to 1 and the second flag information equal to 0 and is configured in the operation point information sample group.

According to another embodiment of the present document, a media file processing apparatus is provided. The media file processing apparatus includes a receiving unit for obtaining a media file including an operation point information sample group and a media file processing unit for parsing the operation point information sample group, wherein the parsing of the operation point information sample group includes: Parsing first flag information for a target layer in (Output Layer Set, OLS), wherein the first flag information indicates whether information on the maximum number of temporal sub-layers for inter-layer prediction exists, the target Parsing second flag information on whether a layer is an output layer, and parsing the information on the maximum number of temporal sub-layers based on the first flag information and the second flag information , the operation point information sample group includes the first flag information and the second flag information, and the information about the maximum number of the temporal sub-layers includes the first flag information equal to 1 and the first flag information equal to 0 2 It is characterized in that it is configured in the operation point information sample group based on the flag information.

According to another embodiment of the present document, there is provided a computer-readable digital storage medium in which a media file generated by a method for generating a media file is stored. A computer-readable digital storage medium, wherein the method comprises configuring first flag information for a target layer in an output layer set (OLS), wherein the first flag information includes a maximum of a temporal sub-layer for inter-layer prediction. Indicating whether information on the number exists, configuring second flag information for whether the target layer is an output layer, the temporal sub-layer based on the first flag information and the second flag information composing the information for the maximum number and generating a media file including a working point information sample group, wherein the actuating point information sample group includes the first flag information and the second flag information and, the information on the maximum number of the temporal sub-layers is configured in the operation point information sample group based on the first flag information equal to 1 and the second flag information equal to 0.

According to this document, since the value of information indicating the maximum number of temporal layers for intra-layer inter-layer prediction may vary depending on the OLS to which the layer belongs, flag information indicating whether the information is signaled and whether the layer is an output layer It may be determined in consideration of whether or not, and through this, signaling redundancy for media file delivery may be reduced and overall coding efficiency may be improved.

According to this document, signaling of information on layer dependency can be performed like the methods proposed in various embodiments, thereby reducing signaling redundancy for media file delivery and improving overall coding efficiency can do it

1 schematically shows an example of a video/image coding system to which embodiments of this document can be applied.

2 is a diagram schematically illustrating a configuration of a video/image encoding apparatus to which embodiments of the present document may be applied.

3 is a diagram schematically illustrating a configuration of a video/image decoding apparatus to which embodiments of the present document may be applied.

4 exemplarily shows a media file creation method to which the embodiment proposed in this document is applied.

5 exemplarily shows a method of decoding a media file generated by applying the embodiment proposed in this document.

6 schematically illustrates a method of generating a media file by a media file generating apparatus according to the present document.

7 schematically shows a media file generating apparatus that performs the media file generating method according to the present document.

8 schematically illustrates a media file processing method by a media file processing apparatus according to the present document.

9 schematically shows a media file processing apparatus for performing a media file processing method according to the present document.

10 exemplarily shows a structural diagram of a content streaming system to which embodiments of this document are applied.

Since this document may have various changes and may have various embodiments, specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the embodiments of the present document to specific embodiments. Terms commonly used herein are used only to describe specific embodiments, and are not intended to limit the technical spirit of the present document. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and includes one or more other features or It should be understood that the existence or addition of numbers, steps, operations, components, parts or combinations thereof is not precluded in advance.

Meanwhile, each configuration in the drawings described in this document is shown independently for the convenience of description regarding different characteristic functions, and does not mean that each configuration is implemented as separate hardware or separate software. For example, two or more components among each component may be combined to form one component, or one component may be divided into a plurality of components. Embodiments in which each component is integrated and/or separated are also included in the scope of the present document without departing from the essence of this document.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of the present document will be described in more detail. Hereinafter, the same reference numerals are used for the same components in the drawings, and repeated descriptions of the same components may be omitted.

Referring to FIG. 1 , a video/image coding system may include a first apparatus (source device) and a second apparatus (receive device). The source device may transmit encoded video/image information or data in the form of a file or streaming to the receiving device through a digital storage medium or a network.

The source device may include a video source, an encoding apparatus, and a transmission unit. The receiving device may include a receiving unit, a decoding apparatus, and a renderer. The encoding apparatus may be referred to as a video/image encoding apparatus, and the decoding apparatus may be referred to as a video/image decoding apparatus. The transmitter may be included in the encoding device. The receiver may be included in the decoding device. The renderer may include a display unit, and the display unit may be configured as a separate device or external component.

The video source may acquire a video/image through a process of capturing, synthesizing, or generating a video/image. A video source may include a video/image capture device and/or a video/image generating device. A video/image capture device may include, for example, one or more cameras, a video/image archive containing previously captured video/images, and the like. A video/image generating device may include, for example, a computer, tablet, and smart phone, and may (electronically) generate a video/image. For example, a virtual video/image may be generated through a computer, etc. In this case, the video/image capturing process may be substituted for the process of generating related data.

The encoding device may encode the input video/image. The encoding apparatus may perform a series of procedures such as prediction, transformation, and quantization for compression and coding efficiency. The encoded data (encoded video/image information) may be output in the form of a bitstream.

The transmitting unit may transmit the encoded video/image information or data output in the form of a bitstream to the receiving unit of the receiving device in the form of a file or streaming through a digital storage medium or a network. The digital storage medium may include a variety of storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD. The transmission unit may include an element for generating a media file through a predetermined file format, and may include an element for transmission through a broadcast/communication network. The receiver may receive/extract the bitstream and transmit it to the decoding device.

The decoding apparatus may decode the video/image by performing a series of procedures such as inverse quantization, inverse transformation, and prediction corresponding to the operation of the encoding apparatus.

The renderer may render the decoded video/image. The rendered video/image may be displayed through the display unit.

This article is about video/image coding. For example, the method/embodiment disclosed in this document is a versatile video coding (VVC) standard, an essential video coding (EVC) standard, an AOMedia Video 1 (AV1) standard, a 2nd generation of audio video coding standard (AVS2) or a next-generation video/ It can be applied to the method disclosed in the image coding standard (ex. H.267 or H.268, etc.).

This document presents various embodiments related to video/image coding, and unless otherwise stated, the embodiments may be combined with each other.

In this document, a video may mean a set of a series of images according to the passage of time. A picture generally means a unit representing one image in a specific time period, and a subpicture/slice/tile is a unit constituting a part of a picture in coding. A subpicture/slice/tile may include one or more coding tree units (CTUs). One picture may be composed of one or more subpictures/slice/tile. One picture may be composed of one or more tile groups. One tile group may include one or more tiles. A brick may indicate a rectangular area of CTU rows within a tile in a picture. A tile may be partitioned into multiple bricks, and each brick may consist of one or more CTU rows within the tile. A tile that is not partitioned into multiple bricks may also be referred to as a brick. A brick scan may indicate a specific sequential ordering of CTUs partitioning a picture, wherein the CTUs may be arranged in a CTU raster scan within a brick, and the bricks within a tile may be sequentially arranged in a raster scan of the bricks of the tile. and tiles in a picture may be sequentially aligned with a raster scan of the tiles of the picture. In addition, a sub-picture may indicate a rectangular region of one or more slices in the picture. That is, the sub-picture may include one or more slices that collectively cover the rectangular area of the picture. A tile is a specific tile row and a rectangular area of CTUs within a specific tile row. The tile column is a rectangular region of CTUs, the rectangular region has a height equal to the height of the picture, and the width may be specified by syntax elements in a picture parameter set. The tile row is a rectangular region of CTUs, the rectangular region has a width specified by syntax elements in a picture parameter set, and the height may be equal to the height of the picture. A tile scan may indicate a specific sequential ordering of CTUs partitioning a picture, wherein the CTUs may be sequentially aligned with a CTU raster scan within a tile, and tiles within a picture may be sequentially aligned with a raster scan of the tiles of the picture. can A slice may include an integer number of bricks of a picture, and the integer number of bricks may be included in one NAL unit. A slice may consist of a number of complete tiles, or it may be a continuous sequence of complete bricks of one tile. In this document, tile group and slice can be used interchangeably. For example, in this document, a tile group/tile group header may be referred to as a slice/slice header.

A pixel or pel may mean a minimum unit constituting one picture (or image). Also, a 'sample' may be used as a term corresponding to a pixel. A sample may generally represent a pixel or a value of a pixel, may represent only a pixel/pixel value of a luma component, or may represent only a pixel/pixel value of a chroma component.

A unit may represent a basic unit of image processing. The unit may include at least one of a specific region of a picture and information related to the region. One unit may include one luma block and two chroma (ex. cb, cr) blocks. A unit may be used interchangeably with terms such as a block or an area in some cases. In a general case, an MxN block may include samples (or sample arrays) or a set (or arrays) of transform coefficients including M columns and N rows.

In this specification, "A or B (A or B)" may mean "only A", "only B", or "both A and B". In other words, in the present specification, "A or B (A or B)" may be interpreted as "A and/or B (A and/or B)". For example, "A, B or C(A, B or C)" herein means "only A", "only B", "only C", or "any and any combination of A, B and C ( any combination of A, B and C)".

As used herein, a slash (/) or a comma (comma) may mean “and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, B, or C”.

As used herein, “at least one of A and B” may mean “only A”, “only B”, or “both A and B”. In addition, in this specification, the expression "at least one of A or B" or "at least one of A and/or B" means "at least one It can be interpreted the same as "A and B (at least one of A and B)".

Also, as used herein, "at least one of A, B and C" means "only A", "only B", "only C", or "A, B and C" any combination of A, B and C". Also, "at least one of A, B or C" or "at least one of A, B and/or C" means can mean “at least one of A, B and C”.

In addition, parentheses used herein may mean "for example". Specifically, when “prediction (intra prediction)” is indicated, “intra prediction” may be proposed as an example of “prediction”. In other words, "prediction" in the present specification is not limited to "intra prediction", and "intra prediction" may be proposed as an example of "prediction". Also, even when “prediction (ie, intra prediction)” is indicated, “intra prediction” may be proposed as an example of “prediction”.

In this specification, technical features that are individually described within one drawing may be implemented individually or simultaneously.

The following drawings were created to explain a specific example of the present specification. Since the names of specific devices described in the drawings or the names of specific signals/messages/fields are presented by way of example, the technical features of the present specification are not limited to the specific names used in the following drawings.

2 is a diagram schematically illustrating a configuration of a video/image encoding apparatus to which embodiments of the present document may be applied. Hereinafter, a video encoding apparatus may include an image encoding apparatus.

2, the encoding apparatus 200 includes an image partitioner 210, a predictor 220, a residual processor 230, an entropy encoder 240, It may be configured to include an adder 250 , a filter 260 , and a memory 270 . The prediction unit 220 may include an inter prediction unit 221 and an intra prediction unit 222 . The residual processing unit 230 may include a transformer 232 , a quantizer 233 , an inverse quantizer 234 , and an inverse transformer 235 . The residual processing unit 230 may further include a subtractor 231 . The adder 250 may be referred to as a reconstructor or a reconstructed block generator. The above-described image segmentation unit 210, prediction unit 220, residual processing unit 230, entropy encoding unit 240, adder 250 and filtering unit 260 may include one or more hardware components ( For example, by an encoder chipset or processor). In addition, the memory 270 may include a decoded picture buffer (DPB), and may be configured by a digital storage medium. The hardware component may further include a memory 270 as an internal/external component.

The image dividing unit 210 may divide an input image (or a picture, a frame) input to the encoding apparatus 200 into one or more processing units. For example, the processing unit may be referred to as a coding unit (CU). In this case, the coding unit is to be recursively divided according to a quad-tree binary-tree ternary-tree (QTBTTT) structure from a coding tree unit (CTU) or largest coding unit (LCU). can For example, one coding unit may be divided into a plurality of coding units having a lower depth based on a quad tree structure, a binary tree structure, and/or a ternary structure. In this case, for example, a quad tree structure may be applied first and a binary tree structure and/or a ternary structure may be applied later. Alternatively, the binary tree structure may be applied first. A coding procedure according to this document may be performed based on the final coding unit that is no longer divided. In this case, the largest coding unit may be directly used as the final coding unit based on coding efficiency according to image characteristics, or the coding unit may be recursively divided into coding units having a lower depth than the optimal coding unit if necessary. A coding unit of the size of may be used as the final coding unit. Here, the coding procedure may include procedures such as prediction, transformation, and restoration, which will be described later. As another example, the processing unit may further include a prediction unit (PU) or a transform unit (TU). In this case, the prediction unit and the transform unit may be divided or partitioned from the above-described final coding unit, respectively. The prediction unit may be a unit of sample prediction, and the transform unit may be a unit for deriving a transform coefficient and/or a unit for deriving a residual signal from the transform coefficient.

A unit may be used interchangeably with terms such as a block or an area in some cases. In general, an MxN block may represent a set of samples or transform coefficients including M columns and N rows. A sample may generally represent a pixel or a value of a pixel, may represent only a pixel/pixel value of a luminance component, or may represent only a pixel/pixel value of a chroma component. A sample may be used as a term corresponding to a picture (or an image) as a pixel or a pel.

The encoding apparatus 200 subtracts the prediction signal (predicted block, prediction sample array) output from the inter prediction unit 221 or the intra prediction unit 222 from the input image signal (original block, original sample array) to obtain a residual A signal (residual signal, residual block, residual sample array) may be generated, and the generated residual signal is transmitted to the converter 232 . In this case, as illustrated, a unit for subtracting a prediction signal (prediction block, prediction sample array) from an input image signal (original block, original sample array) in the encoder 200 may be referred to as a subtraction unit 231 . The prediction unit may perform prediction on a processing target block (hereinafter, referred to as a current block) and generate a predicted block including prediction samples for the current block. The prediction unit may determine whether intra prediction or inter prediction is applied on a current block or CU basis. The prediction unit may generate various information regarding prediction, such as prediction mode information, and transmit it to the entropy encoding unit 240 , as will be described later in the description of each prediction mode. The prediction information may be encoded by the entropy encoding unit 240 and output in the form of a bitstream.

The intra prediction unit 222 may predict the current block with reference to samples in the current picture. The referenced samples may be located in the vicinity of the current block or may be located apart from each other according to the prediction mode. In intra prediction, prediction modes may include a plurality of non-directional modes and a plurality of directional modes. The non-directional mode may include, for example, a DC mode and a planar mode (Planar mode). The directional mode may include, for example, 33 directional prediction modes or 65 directional prediction modes according to the granularity of the prediction direction. However, this is an example, and a higher or lower number of directional prediction modes may be used according to a setting. The intra prediction unit 222 may determine the prediction mode applied to the current block by using the prediction mode applied to the neighboring block.

The inter prediction unit 221 may derive the predicted block for the current block based on the reference block (reference sample array) specified by the motion vector on the reference picture. In this case, in order to reduce the amount of motion information transmitted in the inter prediction mode, the motion information may be predicted in units of blocks, subblocks, or samples based on the correlation between motion information between neighboring blocks and the current block. The motion information may include a motion vector and a reference picture index. The motion information may further include inter prediction direction (L0 prediction, L1 prediction, Bi prediction, etc.) information. In the case of inter prediction, the neighboring blocks may include spatial neighboring blocks existing in the current picture and temporal neighboring blocks present in the reference picture. The reference picture including the reference block and the reference picture including the temporal neighboring block may be the same or different. The temporal neighboring block may be called a collocated reference block, a collocated CU (colCU), or the like, and a reference picture including the temporally neighboring block may be called a collocated picture (colPic). may be For example, the inter prediction unit 221 constructs a motion information candidate list based on neighboring blocks, and provides information indicating which candidate is used to derive a motion vector and/or a reference picture index of the current block. can create Inter prediction may be performed based on various prediction modes. For example, in the skip mode and merge mode, the inter prediction unit 221 may use motion information of a neighboring block as motion information of the current block. In the skip mode, unlike the merge mode, a residual signal may not be transmitted. In the case of motion vector prediction (MVP) mode, the motion vector of the current block is calculated by using a motion vector of a neighboring block as a motion vector predictor and signaling a motion vector difference. can direct

The prediction unit 220 may generate a prediction signal based on various prediction methods to be described later. For example, the prediction unit may apply intra prediction or inter prediction for prediction of one block, and may simultaneously apply intra prediction and inter prediction. This can be called combined inter and intra prediction (CIIP). In addition, the prediction unit may be based on an intra block copy (IBC) prediction mode or based on a palette mode for prediction of a block. The IBC prediction mode or the palette mode may be used for video/video coding of content such as games, for example, screen content coding (SCC). IBC basically performs prediction within the current picture, but may be performed similarly to inter prediction in that a reference block is derived within the current picture. That is, IBC may use at least one of the inter prediction techniques described in this document. The palette mode may be viewed as an example of intra coding or intra prediction. When the palette mode is applied, the sample value in the picture may be signaled based on information about the palette table and palette index.

The prediction signal generated by the prediction unit (including the inter prediction unit 221 and/or the intra prediction unit 222 ) may be used to generate a reconstructed signal or may be used to generate a residual signal. The transform unit 232 may generate transform coefficients by applying a transform technique to the residual signal. For example, the transformation method may include at least one of Discrete Cosine Transform (DCT), Discrete Sine Transform (DST), Karhunen-Loeve Transform (KLT), Graph-Based Transform (GBT), or Conditionally Non-linear Transform (CNT). may include Here, GBT means a transformation obtained from this graph when expressing relationship information between pixels in a graph. CNT refers to a transformation obtained by generating a prediction signal using all previously reconstructed pixels and based thereon. Also, the transformation process may be applied to a block of pixels having the same size as a square, or may be applied to a block of a variable size that is not a square.

The quantization unit 233 quantizes the transform coefficients and transmits them to the entropy encoding unit 240, and the entropy encoding unit 240 encodes the quantized signal (information on the quantized transform coefficients) and outputs it as a bitstream. there is. Information about the quantized transform coefficients may be referred to as residual information. The quantization unit 233 may rearrange the quantized transform coefficients in the block form into a one-dimensional vector form based on a coefficient scan order, and the quantized transform coefficients in the one-dimensional vector form are quantized based on the quantized transform coefficients in the one-dimensional vector form. Information about the transform coefficients may be generated. The entropy encoding unit 240 may perform various encoding methods such as, for example, exponential Golomb, context-adaptive variable length coding (CAVLC), and context-adaptive binary arithmetic coding (CABAC). The entropy encoding unit 240 may encode information necessary for video/image reconstruction (eg, values of syntax elements, etc.) other than the quantized transform coefficients together or separately. Encoded information (eg, encoded video/image information) may be transmitted or stored in a network abstraction layer (NAL) unit unit in a bitstream form. The video/image information may further include information about various parameter sets, such as an adaptation parameter set (APS), a picture parameter set (PPS), a sequence parameter set (SPS), or a video parameter set (VPS). In addition, the video/image information may further include general constraint information. In this document, information and/or syntax elements transmitted/signaled from the encoding device to the decoding device may be included in video/image information. The video/image information may be encoded through the above-described encoding procedure and included in the bitstream. The bitstream may be transmitted over a network or may be stored in a digital storage medium. Here, the network may include a broadcasting network and/or a communication network, and the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD. In the signal output from the entropy encoding unit 240, a transmitting unit (not shown) and/or a storing unit (not shown) for storing may be configured as internal/external elements of the encoding apparatus 200, or the transmitting unit It may be included in the entropy encoding unit 240 .

The quantized transform coefficients output from the quantization unit 233 may be used to generate a prediction signal. For example, a residual signal (residual block or residual samples) may be reconstructed by applying inverse quantization and inverse transform to the quantized transform coefficients through the inverse quantizer 234 and the inverse transform unit 235 . The adder 250 adds the reconstructed residual signal to the prediction signal output from the inter prediction unit 221 or the intra prediction unit 222 to obtain a reconstructed signal (reconstructed picture, reconstructed block, reconstructed sample array). can be created When there is no residual for the block to be processed, such as when the skip mode is applied, the predicted block may be used as a reconstructed block. The addition unit 250 may be called a restoration unit or a restoration block generation unit. The generated reconstructed signal may be used for intra prediction of the next processing object block in the current picture, or may be used for inter prediction of the next picture after filtering as described below.

Meanwhile, luma mapping with chroma scaling (LMCS) may be applied during picture encoding and/or restoration.

The filtering unit 260 may improve subjective/objective image quality by applying filtering to the reconstructed signal. For example, the filtering unit 260 may generate a modified reconstructed picture by applying various filtering methods to the reconstructed picture, and store the modified reconstructed picture in the memory 270 , specifically, the DPB of the memory 270 . can be stored in The various filtering methods may include, for example, deblocking filtering, a sample adaptive offset, an adaptive loop filter, a bilateral filter, and the like. The filtering unit 260 may generate various types of filtering-related information and transmit it to the entropy encoding unit 240 , as will be described later in the description of each filtering method. The filtering-related information may be encoded by the entropy encoding unit 240 and output in the form of a bitstream.

The corrected reconstructed picture transmitted to the memory 270 may be used as a reference picture in the inter prediction unit 221 . When inter prediction is applied through this, the encoding apparatus can avoid prediction mismatch between the encoding apparatus 200 and the decoding apparatus 300, and can also improve encoding efficiency.

The memory 270 DPB may store the corrected reconstructed picture to be used as a reference picture in the inter prediction unit 221 . The memory 270 may store motion information of a block in which motion information in the current picture is derived (or encoded) and/or motion information of blocks in an already reconstructed picture. The stored motion information may be transmitted to the inter prediction unit 221 to be used as motion information of a spatial neighboring block or motion information of a temporal neighboring block. The memory 270 may store reconstructed samples of blocks reconstructed in the current picture, and may transmit the reconstructed samples to the intra prediction unit 222 .

Referring to FIG. 3 , the decoding apparatus 300 includes an entropy decoder 310 , a residual processor 320 , a predictor 330 , an adder 340 , and a filtering unit. (filter, 350) and may be configured to include a memory (memory, 360). The prediction unit 330 may include an inter prediction unit 331 and an intra prediction unit 332 . The residual processor 320 may include a dequantizer 321 and an inverse transformer 322 . The entropy decoding unit 310 , the residual processing unit 320 , the prediction unit 330 , the addition unit 340 , and the filtering unit 350 are one hardware component (eg, a decoder chipset or a processor according to an embodiment). ) can be configured by In addition, the memory 360 may include a decoded picture buffer (DPB), and may be configured by a digital storage medium. The hardware component may further include a memory 360 as an internal/external component.

When a bitstream including video/image information is input, the decoding apparatus 300 may reconstruct an image corresponding to a process in which the video/image information is processed in the encoding apparatus of FIG. 2 . For example, the decoding apparatus 300 may derive units/blocks based on block division related information obtained from the bitstream. The decoding apparatus 300 may perform decoding by using a processing unit applied in the encoding apparatus. Thus, the processing unit of decoding may be, for example, a coding unit, and the coding unit may be divided along a quad tree structure, a binary tree structure and/or a ternary tree structure from a coding tree unit or a largest coding unit. One or more transform units may be derived from a coding unit. In addition, the reconstructed image signal decoded and output through the decoding apparatus 300 may be reproduced through the reproduction apparatus.

The decoding apparatus 300 may receive a signal output from the encoding apparatus of FIG. 2 in the form of a bitstream, and the received signal may be decoded through the entropy decoding unit 310 . For example, the entropy decoding unit 310 may derive information (eg, video/image information) necessary for image restoration (or picture restoration) by parsing the bitstream. The video/image information may further include information about various parameter sets, such as an adaptation parameter set (APS), a picture parameter set (PPS), a sequence parameter set (SPS), or a video parameter set (VPS). In addition, the video/image information may further include general constraint information. The decoding apparatus may decode the picture further based on the information on the parameter set and/or the general restriction information. Signaled/received information and/or syntax elements described later in this document may be decoded through the decoding procedure and obtained from the bitstream. For example, the entropy decoding unit 310 decodes information in a bitstream based on a coding method such as exponential Golomb encoding, CAVLC or CABAC, and a value of a syntax element required for image reconstruction, and a quantized value of a transform coefficient related to a residual can be printed out. In more detail, the CABAC entropy decoding method receives a bin corresponding to each syntax element in the bitstream, and decodes the syntax element information to be decoded and the decoding information of the surrounding and decoding target blocks or the symbol/bin information decoded in the previous step. A context model is determined using the context model, and the probability of occurrence of a bin is predicted according to the determined context model, and a symbol corresponding to the value of each syntax element can be generated by performing arithmetic decoding of the bin. there is. In this case, the CABAC entropy decoding method may update the context model by using the decoded symbol/bin information for the context model of the next symbol/bin after determining the context model. Prediction-related information among the information decoded by the entropy decoding unit 310 is provided to the prediction units (the inter prediction unit 332 and the intra prediction unit 331), and the entropy decoding unit 310 performs entropy decoding. The dual value, that is, the quantized transform coefficients and related parameter information may be input to the residual processing unit 320 . The residual processing unit 320 may derive a residual signal (residual block, residual samples, residual sample array). Also, information about filtering among the information decoded by the entropy decoding unit 310 may be provided to the filtering unit 350 . On the other hand, a receiving unit (not shown) that receives a signal output from the encoding device may be further configured as an internal/external element of the decoding device 300 , or the receiving unit may be a component of the entropy decoding unit 310 . On the other hand, the decoding apparatus according to this document may be called a video/image/picture decoding apparatus, and the decoding apparatus is divided into an information decoder (video/image/picture information decoder) and a sample decoder (video/image/picture sample decoder). may be The information decoder may include the entropy decoding unit 310 , and the sample decoder includes the inverse quantization unit 321 , the inverse transform unit 322 , the adder 340 , the filtering unit 350 , and the memory 360 . ), an inter prediction unit 332 , and at least one of an intra prediction unit 331 .

The inverse quantizer 321 may inverse quantize the quantized transform coefficients to output the transform coefficients. The inverse quantizer 321 may rearrange the quantized transform coefficients in a two-dimensional block form. In this case, the rearrangement may be performed based on the coefficient scan order performed by the encoding device. The inverse quantization unit 321 may perform inverse quantization on the quantized transform coefficients using a quantization parameter (eg, quantization step size information) and obtain transform coefficients.

The inverse transform unit 322 inverse transforms the transform coefficients to obtain a residual signal (residual block, residual sample array).

The prediction unit may perform prediction on the current block and generate a predicted block including prediction samples for the current block. The prediction unit may determine whether intra prediction or inter prediction is applied to the current block based on the prediction information output from the entropy decoding unit 310, and may determine a specific intra/inter prediction mode.

The prediction unit 320 may generate a prediction signal based on various prediction methods to be described later. For example, the prediction unit may apply intra prediction or inter prediction for prediction of one block, and may simultaneously apply intra prediction and inter prediction. This can be called combined inter and intra prediction (CIIP). In addition, the prediction unit may be based on an intra block copy (IBC) prediction mode or based on a palette mode for prediction of a block. The IBC prediction mode or the palette mode may be used for video/video coding of content such as games, for example, screen content coding (SCC). IBC basically performs prediction within the current picture, but may be performed similarly to inter prediction in that a reference block is derived within the current picture. That is, IBC may use at least one of the inter prediction techniques described in this document. The palette mode may be viewed as an example of intra coding or intra prediction. When the palette mode is applied, information about a palette table and a palette index may be included in the video/image information and signaled.

The intra prediction unit 331 may predict the current block with reference to samples in the current picture. The referenced samples may be located in the vicinity of the current block or may be located apart from each other according to the prediction mode. In intra prediction, prediction modes may include a plurality of non-directional modes and a plurality of directional modes. The intra prediction unit 331 may determine the prediction mode applied to the current block by using the prediction mode applied to the neighboring block.

The inter prediction unit 332 may derive the predicted block for the current block based on the reference block (reference sample array) specified by the motion vector on the reference picture. In this case, in order to reduce the amount of motion information transmitted in the inter prediction mode, the motion information may be predicted in units of blocks, subblocks, or samples based on the correlation between motion information between neighboring blocks and the current block. The motion information may include a motion vector and a reference picture index. The motion information may further include inter prediction direction (L0 prediction, L1 prediction, Bi prediction, etc.) information. In the case of inter prediction, the neighboring blocks may include spatial neighboring blocks existing in the current picture and temporal neighboring blocks present in the reference picture. For example, the inter prediction unit 332 may construct a motion information candidate list based on neighboring blocks, and derive a motion vector and/or a reference picture index of the current block based on the received candidate selection information. Inter prediction may be performed based on various prediction modes, and the information on the prediction may include information indicating the mode of inter prediction for the current block.

The adder 340 restores the obtained residual signal by adding it to the prediction signal (predicted block, prediction sample array) output from the prediction unit (including the inter prediction unit 332 and/or the intra prediction unit 331 ). A signal (reconstructed picture, reconstructed block, reconstructed sample array) may be generated. When there is no residual for the block to be processed, such as when the skip mode is applied, the predicted block may be used as a reconstructed block.

The adder 340 may be referred to as a restoration unit or a restoration block generator. The generated reconstructed signal may be used for intra prediction of the next processing target block in the current picture, may be output through filtering as described below, or may be used for inter prediction of the next picture.

Meanwhile, luma mapping with chroma scaling (LMCS) may be applied in the picture decoding process.

The filtering unit 350 may improve subjective/objective image quality by applying filtering to the reconstructed signal. For example, the filtering unit 350 may generate a modified reconstructed picture by applying various filtering methods to the reconstructed picture, and convert the modified reconstructed picture to the memory 360 , specifically, the DPB of the memory 360 . can be sent to The various filtering methods may include, for example, deblocking filtering, a sample adaptive offset, an adaptive loop filter, a bilateral filter, and the like.

The (modified) reconstructed picture stored in the DPB of the memory 360 may be used as a reference picture in the inter prediction unit 332 . The memory 360 may store motion information of a block in which motion information in the current picture is derived (or decoded) and/or motion information of blocks in an already reconstructed picture. The stored motion information may be transmitted to the inter prediction unit 260 to be used as motion information of a spatial neighboring block or motion information of a temporal neighboring block. The memory 360 may store reconstructed samples of blocks reconstructed in the current picture, and may transmit the reconstructed samples to the intra prediction unit 331 .

In this specification, the embodiments described in the filtering unit 260 , the inter prediction unit 221 , and the intra prediction unit 222 of the encoding apparatus 200 are the filtering unit 350 and the inter prediction unit of the decoding apparatus 300 , respectively. The same or corresponding application may be applied to the unit 332 and the intra prediction unit 331 .

Meanwhile, the above-described encoded image/video information may be configured based on a media file format to generate a media file. For example, the encoded image/video information may form a media file (segment) based on one or more NAL unit/sample entries for the encoded image/video information. The media file may include sample entries and tracks. For example, a media file (segment) may include various records, and each record may include information related to an image/video or information related to a media file format. Also, for example, one or more NAL units may be stored in a configuration record (or decoder configuration record, or VVC decoder configuration record) field of the media file. Here, the field may be referred to as a syntax element. Also, for example, the media file may include VvcOperatingPointsRecord (operation point information sample group) and/or OperatingPointGroupBox (operation point entity group), which will be described later.

For example, ISO Base Media File Format (ISOBMFF) may be used as a media file format to which the method/embodiment disclosed in this document can be applied. ISOBMFF supports many codec encapsulation formats, such as AVC file format, HEVC file format and/or VVC file format, and MPEG-4 file format, 3GPP file format (3GP) and/or DVB file format, etc. It can be used as the basis for many multimedia container formats. Further, in addition to continuous media such as audio and video, static media such as an image and metadata may be stored in a file according to ISOBMFF. Files structured according to ISOBMFF include segments for local media file playback, progressive downloading of a remote file, Dynamic Adaptive Streaming over HTTP (DASH), It can be used for various purposes, such as containers of content to be streamed, packetization instructions, and recording of received real-time media streams.

A 'box', which will be described later, may be an elementary syntax element of ISOBMFF. An ISOBMFF file may consist of a sequence of boxes, which may contain other boxes. For example, a movie box (a box with a grouping type of 'moov') may contain metadata for continuous media streams in a media file, each stream being a track in the file. can be displayed. Metadata about a track may be included in a track box (a box having a grouping type of 'trak'), and media content of the track may be included in a media data box (a grouping type of 'mdat'). in-box) or directly in a separate file. The media content of a track may consist of a sequence of samples, such as audio or video access units. For example, ISOBMFF includes a media track including an elementary media stream, a hint track including media transmission instructions or indicating a received packet stream, a time You can specify types of tracks such as a timed metadata track containing timesynchronized metadata.

ISOBMFF is also designed for storage, but is also very useful, for example, for progressive download or streaming like DASH. For streaming purposes, movie fragments defined in ISOBMFF may be used. A fragmented ISOBMFF file may be represented by, for example, two tracks related to video and audio. For example, if random access is included after receiving the 'moov' box, all movie fragments 'moof' together with related media data may be decoded.

In addition, the metadata of each track may include a list of sample description entries that provide the coding or encapsulation format used for the track and initialization data necessary to process the format. there is. Also, each sample may be associated with one of the sample description entries of the track.

ISOBMFF allows a variety of mechanisms to specify sample-specific metadata. Specific boxes in the sample table box (box with grouping type 'stbl') can be standardized to correspond to general requirements. For example, a Sync sample box (a box with a grouping type of 'stss') may be used to list random access samples of a track. Using the sample grouping mechanism, you can map samples according to a four-character grouping type into a sample group that shares the same property specified by the sample group description entry in the file. there is. Several grouping types may be specified in ISOBMFF.

Meanwhile, a 'sample' to be described later may be all data related to one single time or a single element among three sample arrays (Y, Cb, Cr) representing a picture. For example, when the term 'sample' is used in the context of a track (in a media file format), it may mean all data related to a single time of the corresponding track. Here, the time may be a decoding time or a composition time. Also, for example, when the term 'sample' is used in the context of a picture, that is, when used with the phrase "luma sample", a three sample array representing a picture It can represent a single element in one of them.

Meanwhile, in order to store VVC content, the following three types of elementary streams may be defined.

- a video elementary stream that does not contain a parameter set. Here, all parameter sets may be stored in a sample entry or sample entries.

- a video and parameter set elementary stream which may contain a parameter set and has a sample entry or sample entries in which the parameter sets are stored.

- A non-VCL elementary stream containing non-VCL NAL units synchronized with the elementary stream included in the video track. Here, the VVC non-VCL track does not include a parameter set in sample entries.

On the other hand, the operating point information (operating points information) of the ISO based media file format (ISOBMF) for VVC is a group box or grouping type in which the grouping type is 'vopi' It may be signaled as a sample in an entity group that is 'opeg'. Here, the operating point may be a temporal subset of the OLS identified by the highest value of the OLS (Output Layer Set, OLS) index and TemporalId. Each actuation point may be associated with a profile, tier and level (ie, a PTL) that defines the conformance point of the actuation point. The actuation point information may be needed to identify a sample and a sample entry for each actuation point.

Applications may be provided with various actuation points provided by a given VVC bitstream and information on the constitution of the actuation points using an actuation point information sample group ('vopi'). Each actuation point is associated with OLS, maximum TemporalId value, profile, level and tier signaling. All of the above information can be captured by the 'vopi' sample group. Apart from the above information, the sample group may also provide dependency information between layers.

Meanwhile, when one or more VVC tracks exist for a VVC bitstream and an Operating Point entity group does not exist for a VVC bitstream, all of the following may be applied.

- Among the VVC tracks for the VVC bitstream, there must be only one track carrying the 'vopi' sample group.

- All other VVC tracks of the VVC bitstream must have a track reference of type 'oref' to the track carrying the 'vopi' sample group.

Also, with respect to a specific sample of a given track, a temporally collocated sample of another track may be defined as a sample having the same decoding time as the specific sample. For each sample SN of track TN with 'oref' track reference to track Tk carrying 'vopi' sample group, the following may apply.

- If there is a temporally collocated sample Sk in the track Tk, the sample SN may be associated with the same 'vopi' sample group entity as the sample Sk.

- otherwise, the sample SN may be associated with the same vopi' sample group entity as the last sample of the track Tk preceding the sample SN in decoding time.

When several VPSs are referenced in the VVC bitstream, it may be necessary to include several entities in a sample group description box with grouping_type 'vopi'. In the more general case with a single VPS, use the default sample group mechanism defined in ISO/IEC 14496-12 and not include it in each track fragment, but instead put the operating point information in the sample table box. It may be recommended to include (operating points information sample group).

Also, grouping_type_parameter may not be defined for SampleToGroupBox whose grouping type is 'vopi'.

The syntax of the 'vopi' sample group including the above-described operating point information, that is, the operating point information sample group, may be as shown in the table below.

In addition, semantics of the syntax of the operation point information sample group may be as shown in the following table.

For example, referring to Table 2, a value obtained by adding 1 to the syntax element num_profile_tier_level_minus1 may indicate the number of fields related to profiles, tiers, and level combinations.

In addition, for example, referring to Table 2 above, the syntax element ptl_max_temporal_id[i] represents the maximum TemporalID of NAL units of the bitstream for the specified i-th profile, tier, and level (profiles, tier, level structure, PTL) structure. can That is, for example, the syntax element ptl_max_temporal_id[i] may indicate the maximum value of the temporal ID (TemporalID) of the NAL unit of the bitstream for the i-th PTL structure. Meanwhile, ptl_max_temporal_id[i] and max_temporal_id of the actuation point may transmit the same value, but semantics of the syntax elements are different.

Also, for example, referring to Table 2 above, the syntax element ptl[i] may indicate an i-th PTL structure.

Also, for example, referring to Table 2, the syntax elements all_independent_layers_flag, each_layer_is_an_ols_flag, ols_mode_idc, and max_tid_il_ref_pics_plus1 may be as defined in ISO/IEC 23090-3. Here, ISO/IEC 23090-3 refers to a versatile video coding (VVC) standard.

Specifically, for example, the syntax element all_independent_layers_flag may indicate whether all layers of the bitstream for the operating point information sample group are independently coded without using interlayer prediction. For example, all_independent_layers_flag equal to 1 may indicate that all layers are independently coded without using inter-layer prediction. Also, for example, all_independent_layers_flag equal to 0 may indicate that at least one or more layers may use interlayer prediction. When the all_independent_layers_flag does not exist, the all_independent_layers_flag may be considered equal to 1 (inferred).

Also, for example, the syntax element each_layer_is_an_ols_flag indicates that each Output Layer Set (OLS) (of the bitstream) for a group of operating point information samples contains only one layer, and the one layer containing each layer is the only output layer. It can indicate whether it is OLS or not. For example, each_layer_is_an_ols_flag equal to 1 may indicate that each output layer set (OLS) includes only one layer and that one layer including each layer is an OLS that is the only output layer. Also, for example, each_layer_is_an_ols_flag equal to 0 may indicate that at least one OLS includes two or more layers.

Also, for example, the syntax element vps_ols_mode_idc may indicate the mode of OLS. For example, vps_ols_mode_idc equal to 0 means that the total number of OLSs is equal to vps_max_layers_minus1 + 1, the i-th OLS includes layers with layer indices from 0 to i, and only the highest layer of each OLS is an output layer. can indicate Also, for example, vps_ols_mode_idc equal to 1 may indicate that the total number of OLSs is equal to vps_max_layers_minus1 + 1, the i-th OLS includes layers with layer indices from 0 to i, and all layers of each OLS are output layers. there is. Also, for example, in vps_ols_mode_idc equal to 2, the total number of OLSs is explicitly signaled, an output layer of each OLS is explicitly signaled, and layers other than the output layer are direct of the output layer of the corresponding OLS. Alternatively, it may indicate that the layer is an indirect reference layer.

Also, for example, the syntax element max_tid_il_ref_pics_plus1 may indicate a maximum temporal sub-layer required for inter-layer prediction in a layer. That is, for example, the syntax element max_tid_il_ref_pics_plus1 may indicate the maximum number of temporal sub-layers required for inter-layer prediction in a layer. For example, a value obtained by subtracting 1 from the syntax element max_tid_il_ref_pics_plus1 may indicate the maximum number of temporal sub-layers required for inter-layer prediction in a layer. In addition, for example, max_tid_il_ref_pics_plus1 equal to 0 is not an Intra Random Access Point (IRAP) picture and a Gradual Decoding Refresh (GDR) picture with ph_recovery_poc_cnt equal to 0. It may indicate that it is not used as an inter-layer reference picture (ILRP) for decoding a picture of a layer. Here, ILRP may indicate a reference picture used for inter-layer prediction. Also, for example, max_tid_il_ref_pics_plus1 greater than 0 is not used as an ILRP, and a picture of a layer with a TemporalId greater than max_tid_il_ref_pics_plus1 - 1 (that is, max_tid_il_ref_pics_plus1 minus 1) is not used for decoding pictures in other layers of the OLS. An APS having nuh_layer_id equal to layer_id and TemporalId greater than max_tid_il_ref_pics_plus1 - 1 (ie, max_tid_il_ref_pics_plus1 minus 1) may indicate that it is not referenced. Meanwhile, when the max_tid_il_ref_pics_plus1 does not exist, the value of max_tid_il_ref_pics_plus1 may be considered to be the same as max_temporal_id.

Also, for example, referring to Table 2, the syntax element num_operating_points may indicate the number of operating points for information to be described later.

Also, for example, referring to Table 2 above, the syntax element output_layer_set_idx may be an index of an OLS defining an operation point. That is, for example, output_layer_set_idx may indicate OLS. The mapping between the output_layer_set_idx and the layer_id value may be the same as that specified by the VPS with respect to the OLS having the index output_layer_set_idx (ie, the OLS indicated by output_layer_set_idx).

Also, for example, referring to Table 2, the syntax element ptl_idx may signal an index starting from 0 in the PTL structure listed for the OLS that is the index output_layer_set_idx. That is, for example, ptl_idx may indicate a PTL structure for OLS whose index is output_layer_set_idx.

Also, for example, referring to Table 2 above, the syntax element max_temporal_id may indicate the maximum TemporalId of the NAL unit of the operation point. Meanwhile, the maximum TemporalId value indicated in the layer information sample group may have the same value as the TemporalId indicated by max_temporal_id, but semantics of the syntax elements are different.

Also, for example, referring to Table 2, the syntax element layer_count may indicate the number of layers required for an operation point as defined in ISO/IEC 23090-3.

Also, for example, referring to Table 2 above, the syntax element layer_id may indicate a nuh_layer_id value for the layer of the operation point. That is, for example, the syntax element layer_id may indicate a layer ID value for the layer of the operation point.

Also, for example, referring to Table 2 above, the syntax element is_outputlayer may indicate whether a layer is an output layer. For example, is_outputlayer equal to 1 may indicate that the layer is an output layer.

Also, for example, referring to Table 2 above, the syntax element frame_rate_info_flag may indicate whether frame rate information for an operation point exists. For example, frame_rate_info_flag equal to 0 may indicate that frame rate information for the operating point does not exist. Also, for example, frame_rate_info_flag equal to 1 may indicate that frame rate information for an operating point exists.

Also, for example, referring to Table 2 above, the syntax element bit_rate_info_flag may indicate whether bitrate information for an operation point exists. For example, bit_rate_info_flag equal to 0 may indicate that bitrate information for the operating point does not exist. Also, for example, bit_rate_info_flag equal to 1 may indicate that bitrate information for an operating point exists.

Also, for example, referring to Table 2 above, the syntax element avgFrameRate may provide the average frame rate for the operation point in units of frames/(256 seconds). A value of 0 may represent an unspecified average frame rate.

Also, for example, referring to Table 2 above, the syntax element constantFrameRate may indicate a constant frame rate for a stream of an operation point. For example, constantFrameRate equal to 1 may indicate that the stream of the actuation point is a constant frame rate. constantFrameRate equal to the value 2 may indicate that the representation of each temporal layer in the stream of the actuation point is a constant frame rate. constantFrameRate equal to the value 0 may indicate that the stream of the actuation point may or may not be a constant frame rate.

Also, for example, referring to Table 2 above, the syntax element maxBitRate may provide the maximum bit rate of the stream of the operation point in all windows of 1 second in bits/second unit.

Also, for example, referring to Table 2 above, the syntax element max_layer_count may indicate the number of all unique layers of all operation points related to an associated base track.

Also, for example, referring to Table 2, the syntax element layerID may indicate nuh_layer_id of a layer in which all direct reference layers are provided in a following loop of direct_ref_layerID.

Also, for example, referring to Table 2, the syntax element num_direct_ref_layers may indicate the number of direct reference layers for a layer having the same nuh_layer_id as layerID.

Also, for example, referring to Table 2 above, the syntax element direct_ref_layerID may indicate the nuh_layer_id of the direct reference layer.

Also, for example, an actuation point entity group may be defined to provide a mapping of tracks to actuation points and profile level information of actuation points.

When aggregating samples of tracks mapped to actuation points described in the actuation point entity group, the implicit reconstruction process generates more NAL units to obtain a conforming VVC bitstream. no need to remove A track belonging to the actuation point entity group must have a track reference of type 'oref' for the group_id indicated in the actuation point entity group.

In addition, all entity_id values included in the operation point entity group must belong to the same VVC bitstream. If present, the OperatingPointGroupBox is included in the Movie-level MetaBox's GroupsListBox and not the file-level or track-level MetaBox. Here, OperatingPointGroupBox may indicate the operating point entity group.

The syntax of the above-described operation point entity group may be as shown in the table below.

In addition, semantics of the syntax of the operation point entity group may be as shown in the following table.

Also, for example, the media file may include decoder configuration information for image/video content. That is, the media file may include a VVC decoder configuration record including decoder configuration information.

When the VVC decoder configuration record is stored in a sample entry, the VVC decoder configuration record includes a length field used for each sample to indicate not only a parameter set but also a length of a NAL unit included in the VVC decoder configuration record. field) size. The VVC decoder configuration record may be externally framed (the size of the VVC decoder configuration record is provided in a structure including the VVC decoder configuration record).

In addition, the VVC decoder configuration record may include a version field (versio field). For example, the version in this document may define version 1 of the VVC decoder configuration record. Incompatible changes to the VVC decoder configuration record may be marked as version number changes. If the version number is not recognized, readers should not decode the VVC decoder configuration record or the stream to which the record applies.

Compatible extensions for the VVC decoder configuration record may not change the configuration version code. The reader must be prepared to ignore unrecognized data that goes beyond the definition of data that the reader understands.

If a track contains the VVC bitstream by default or if resolved via 'subp' track references, VvcPtlRecord must be present in the decoder configuration record. Also, if ptl_present_flag in the decoder configuration record of a track is 0, the track must have an 'oref' track reference.

When the stream described in the VVC decoder configuration record is decoded, values of syntax elements of VvcPTRecord, chroma_format_idc, and bit_depth_minus8 may be valid for all activated parameter sets. In particular, the following restrictions may apply:

- profile indication general_profile_idc indicates the profile to which the stream associated with this configuration record conforms.

A tier indication general_tier_flag may indicate a tier greater than or equal to the highest tier indicated in all parameter sets.

Each bit of general_constraint_info can be set only when all parameter sets set the corresponding bit.

The level indication general_level_idc may indicate a level of capability equal to or greater than the highest level indicated for the highest tier in the parameter sets.

In addition, the following constraint may be applied to chroma_format_idc.

- If the value of sps_chroma_format_idc defined in ISO/IEC 23090-3 is the same in all SPSs referenced by the NAL unit of the track, chroma_format_idc shall be equal to sps_chroma_format_idc.

- Otherwise, if ptl_present_flag is equal to 1, chroma_format_idc shall be equal to vps_ols_dpb_chroma_format[output_layer_set_idx] defined in ISO/IEC 23090-3.

- Otherwise (that is, if the above conditions are not met), chroma_format_idc does not exist.

An explicit indication of a chroma format and bit depth as well as other important format information used in the VVC video elementary stream may be provided in the VVC decoder configuration record. If color space indications are different in the VUI information of the two sequences, two different VVC sample entries may be required.

Also, for example, there may be a set of arrays carrying initialization NAL units in the VVC decoder configuration record. The NAL unit types may be limited to indicate only DCI, VPS, SPS, PPS, prefix APS and prefix SEI NAL units. In ISO/IEC 23090-3 and this document, the reserved NAL unit type may be defined in the future, and the reader may have to ignore the reserved or disallowed values of the NAL unit type array.

Meanwhile, the arrays may be in the order of DCI, VPS, SPS, PPS, prefix APS, and prefix SEI.

The syntax of the above-described VVC decoder configuration record may be as shown in the table below.

In addition, semantics of the syntax of the VVC decoder configuration record may be as shown in the following table.

For example, referring to Table 6 above, syntax elements general_profile_idc, general_tier_flag, general_sub_profile_idc, general_constraint_info, general_level_idc, ptl_frame_only_constraint_flag, ptl_multilayer_enabled_flag, sublayer_level_present and sublayer_level_idc [ Fields for the applied stream may include matching values of general_profile_idc, general_tier_flag, general_sub_profile_idc, bits of general_constraint_info(), general_level_idc, ptl_multilayer_enabled_flag, ptl_frame_only_constraint_flag, sublayer_level_present, and sublayer_level_idc[i]. Here, avgFrameRate may provide the average frame rate of the stream to which the VVC decoder configuration record is applied in units of frames/(256 seconds). A value of 0 may represent an unspecified average frame rate.

Also, for example, referring to Table 6, the syntax element constantFrameRate may indicate a constant frame rate for the VVC decoder configuration record. For example, constantFrameRate equal to 1 may indicate that a stream to which the VVC decoder configuration record is applied is a constant frame rate. constantFrameRate equal to the value 2 may indicate that the representation of each temporal layer of the stream is a constant frame rate. constantFrameRate equal to the value 0 may indicate that the stream may or may not be at a constant frame rate.

Also, for example, referring to Table 6, the syntax element numTemporalLayers may indicate the number of temporal layers included in a track to which the VVC decoder configuration record is applied. For example, if numTemporalLayers is greater than 1, the track to which the VVC decoder configuration record is applied is temporally scalable, and a temporal layer included in the track (a temporal sublayer or sublayer in ISO/IEC 23090-3) ) may indicate that the number of numTemporalLayers is the same as numTemporalLayers. numTemporalLayers equal to the value 1 may indicate that the track to which the VVC decoder configuration record is applied is not temporally scalable. numTemporalLayers equal to the value 0 may indicate that it is not known whether the track to which the VVC decoder configuration record is applied is temporally expandable.

Also, for example, referring to Table 6 above, the syntax element lengthSizeMinusOne plus 1 may indicate the length in bytes of the NALUnitLength field in the VVC video stream sample of the stream to which this configuration record is applied. For example, the size of 1 byte may be represented by the value 0. The value of lengthSizeMinusOne may be one of 0, 1, or 3, which corresponds to an encoded length of 1, 2, or 4 bytes, respectively.

Also, for example, referring to Table 6 above, the syntax element ptl_present_flag may indicate that the track includes a VVC bitstream corresponding to a specific output layer set, and thus may indicate whether PTL information is included. For example, ptl_present_flag equal to 1 may indicate that the track contains a VVC bitstream corresponding to a specific output layer set (specific OLS). ptl_present_flag equal to 0 means that the track may not contain the VVC bitstream corresponding to a particular OLS, but rather one or more individual layers that do not form an OLS or individual sublayers except for those with TemporalId equal to 0. may indicate that it may include

Also, for example, referring to Table 6, the syntax element num_sub_profiles may define the number of sub-profiles indicated in the VVC decoder configuration record.

Also, for example, referring to Table 6, the syntax element track_ptl may indicate a profile, a tier, and a level of an OLS indicated by a VVC bitstream included in a track.

Also, for example, referring to Table 6, the syntax element output_layer_set_idx may indicate an output layer set index of an output layer set indicated by a VVC bitstream included in a track. The value of output_layer_set_idx may be used as the value of the TargetOlsIdx variable provided by an external means to the VVC decoder, as specified in ISO/IEC 23090-3, in order to decode the bitstream included in the track.

Also, for example, referring to Table 6 above, the syntax element chroma_format_present_flag may indicate whether chroma_format_idc exists. For example, chroma_format_present_flag equal to 0 may indicate that chroma_format_idc does not exist. chroma_format_present_flag equal to 1 may indicate that chroma_format_idc exists.

Also, for example, referring to Table 6, the syntax element chroma_format_idc may indicate a chroma format applied to the track. For example, the following constraint may be applied to chroma_format_idc.

Also, for example, referring to Table 6, the syntax element bit_depth_present_flag may indicate whether bit_depth_minus8 exists. For example, bit_depth_present_flag equal to 0 may indicate that bit_depth_minus8 does not exist. bit_depth_present_flag equal to 1 may indicate that bit_depth_minus8 exists.

Also, for example, referring to Table 6, the syntax element bit_depth_minus8 may indicate a bit depth applied to the track. For example, the following constraint may be applied to bit_depth_minus8.

- If the value of sps_bitdepth_minus8 defined in ISO/IEC 23090-3 is the same in all SPSs referenced by the NAL unit of the track, bit_depth_minus8 shall be equal to sps_bitdepth_minus8.

- Otherwise, if ptl_present_flag is equal to 1, bit_depth_minus8 shall be equal to vps_ols_dpb_bitdepth_minus8[output_layer_set_idx] defined in ISO/IEC 23090-3.

- Otherwise (that is, if the above conditions are not met), bit_depth_minus8 does not exist.

Also, for example, referring to Table 6 above, the syntax element numArrays may indicate the number of NAL unit arrays of the indicated type(s).

Also, for example, referring to Table 6 above, the syntax element array_completeness may indicate whether an additional NAL unit may be in the stream. For example, when array_completeness is equal to 1, it may indicate that all NAL units of a given type are in the next array and not in the stream. Also, for example, when array_completeness is equal to 0, it may indicate that an additional NAL unit of the indicated type may be present in the stream. Default and allowed values may be limited to a sample entry name.

Also, for example, referring to Table 6 above, the syntax element NAL_unit_type may indicate the type of the NAL unit in the following array (must be all types). NAL_unit_type may have a value defined in ISO/IEC 23090-2. In addition, NAL_unit_type may be limited to have one of a value indicating a DCI, VPS, SPS, PPS, APS, prefix SEI or suffix SEI NAL unit.

Also, for example, referring to Table 6, the syntax element numNalus may indicate the number of NAL units of the indicated type included in the VVC decoder configuration record for a stream to which the VVC decoder configuration record is applied. The SEI array may include only 'declarative' SEI messages, that is, messages that provide information about the entire stream. An example of such an SEI may be user-data SEI (user-data SEI).

Also, for example, referring to Table 6, the syntax element nalUnitLength may indicate the byte length of the NAL unit.

Also, for example, nalUnit may include DCI, VPS, SPS, PPS, APS or declarative SEI NAL units specified in ISO/IEC 23090-3.

Meanwhile, an operating point may be determined first to reconstruct an access unit from samples of multiple tracks carrying a multi-layer VVC bitstream. For example, when a VVC bitstream is represented by a plurality of VVC tracks, a file parser may identify tracks necessary for the selected operating point as follows.

For example, the file parser can find all tracks with VVC sample entries. If the tracks include an 'oref' track reference for the same ID, the ID can be identified as a VVC track or an 'opeg' entity group. The operating point can be selected from either the 'opeg' entity group or the 'vopi' sample group suitable for decoding capacity and application purposes.

The 'opeg' entity group, if present, may represent a set of tracks that accurately represent the selected operating point. Thus, the VVC bitstream can be recovered from the set of tracks and can be decoded.

Also, if the 'opeg' entity group does not exist (i.e., a 'vopi' sample group exists), the set of tracks needed to decode the selected operating point is retrieved from the 'vopi' and 'linf' sample groups. can

In order to recover the bitstream from a plurality of VVC tracks carrying the VVC bitstream, it may be necessary to first determine the target maximum value TemporalId. When a plurality of tracks include data for an access unit, the alignment of each sample in the tracks may be performed based on sample decoding times. That is, it is possible to use a time-to-sample table without considering edit lists.

When a VVC bitstream is represented by a plurality of VVC tracks, if the tracks are combined into a single stream by increasing the decoding time, the decoding times of the samples are adjusted so that the access unit order is correct as specified in ISO/IEC 23090-3. may have to Meanwhile, a sequence of access units may be reconstructed from each sample of necessary tracks according to an implicit reconstructing process described below. For example, the implicit restoration process of the VVC bitstream may be as follows.

For example, if an Operating Points Information sample group exists, the required track may be selected based on the conveying layer and the reference layer as indicated in the Operating Points Information and Layer Information sample group.

Also, for example, when an Operating Points Entity Group exists, a necessary track may be selected based on information of the OperatingPointGroupBox.

Also, for example, when a VCL NAL unit reconstructs a bitstream including a sublayer having a TemporalId greater than 0, all lower sublayers in the same layer (that is, a sublayer having a smaller TemporalId in the VCL NAL unit) ) are also included in the resulting bitstream and the required track can be selected accordingly.

Also, for example, when reconstructing an access unit, picture units (as defined in ISO/IEC 23090-3) from samples having the same decoding time may be placed in the access unit in an ascending order of the nuh_layer_id value.

Also, for example, if the access unit is restored to dependent layers and max_tid_il_ref_pics_plus1 is greater than 0, max_tid_il_ref_pics_plus1 - 1 (indicated in the operation point information sample group) in the same layer VCL NAL with TemporalId less than or equal to Sublayers of layers for a unit are also included in the resulting bitstream and the required track can be selected accordingly.

Also, for example, if a VVC track contains a 'subp' track reference, then each picture unit is specified in clause 11.7.3 of ISO/IEC 23090-3 with additional restrictions for EOS and EOB NAL units specified below can be restored as The process of clause 11.7.3 of ISO/IEC 23090-3 may be repeated for each layer of the target operating point in increasing order of nuh_layer_id. Otherwise, each picture unit may be reconstructed as follows.

The restored access units may be placed in the VVC bitstream in increasing order of decoding time, and, as further described below, duplicates of end of bitstream (EOB) and end of sequence (EOS) NAL units may be removed from the VVC bitstream.

Also, for example, for access units within the same coded video sequence of a VVC bitstream and belonging to different sublayers stored in multiple tracks, one or more containing an EOS NAL unit with a specific nuh_layer_id value in each sample. There may be tracks. In this case, only one of the EOS NAL units may be maintained in the last access unit (the unit with the largest decoding time) among the access units in the last reconstructed bitstream, and the EOB NAL of the last access unit among the access units It may be placed after all NAL units except for units (if present), and other EOS NAL units may be deleted. Similarly, there may be more than one track containing an EOB NAL unit in each sample. In this case, only one of the EOB NAL units may be maintained in the last reconstructed bitstream, may be placed at the last end of these access units, and the other EOB NAL units may be deleted.

Also, since, for example, a particular layer or sub-layer may be represented by more than one track, when figuring out the required track for an actuation point, one has to choose from among a set of tracks carrying both said particular layer or sub-layer. may be

Also, for example, if an operation point entity group does not exist, after selecting from among the tracks carrying the same layer or sublayer, the final required track still collectively selects some layers or sublayers that do not belong to the target operation point. can transmit The reconstructed bitstream for the target operating point is delivered in the final required track, but layers or sub-layers that do not belong to the target operating point may not be included.

On the other hand, the design of the signaling for the above-described operating point may have the following problems.

Specifically, in the above-described OperatingPointGroupBox, for each operating point, information on the number of layers, a layer ID, whether a layer is an output layer, etc. can be signaled to an output layer set (OLS) related to each operating point. there is. Also, information on layer dependency may be included in the OLS. Here, since signaling of the layer dependency is not required, there may be redundancy of signaling. The information on the layer dependency may help a parser to understand the layer included in each OLS, but the information on each operation point already includes the OLS index and information on the layer list included in the OLS. Since it is included, it may no longer be necessary to signal information about the layer dependency.

In addition, the advantages of signaling of all_independent_layers_flag, each_layer_is_an_ols_flag, and ols_mode_idc described above are not clear. Accordingly, it may be better to simply remove the signaling of the above-described syntax elements.

In addition, the OperatingPointGroupBox syntax structure may include signaling for the maximum number of temporal sublayers (ie, max_tid_il_ref_pics_plus1) for each layer in addition to signaling for layer dependencies. Here, since the value of max_tid_il_ref_pics_plus1 for the layer may be different depending on the OLS to which the layer belongs, it may be necessary to organize the signaling of the information.

Accordingly, this document proposes a solution to the above-described problem. The proposed embodiments may be applied individually or in combination.

As an example, in order to signal information on the operation point, the layer list included in the OLS and the OLS for the output layer set for the operation point (ie, the OLS designated by the OLS index for the operation point) Instead of signaling information indicating whether an included layer is an output layer, only a list of layers that are output layers may be signaled. That is, for example, with respect to the OLS for the operating point, an output layer included in the OLS instead of a method of signaling the layer list included in the existing OLS and information indicating whether a layer included in the OLS is an output layer A method of signaling the in-layer list may be proposed. A complete list of layers required for the OLS may be derived based on a list of layers that are output layers and layer dependency information. Through the method of this embodiment, it is possible to reduce the amount of bits compared to the conventional signaling for OLS and to improve coding efficiency. Here, the derivation of the entire list may be the same as the derivation process specified in the VVC specification.

Also, as an example, signaling of all_independent_layers_flag, each_layer_is_an_ols_flag, and ols_mode_idc may be deleted. That is, for example, a method of not signaling all_independent_layers_flag, each_layer_is_an_ols_flag, and ols_mode_idc in VvcOperatingPointsRecord may be proposed.

Also, as an example, the signaling of the layer dependency information may be moved to a position before the signaling of the operation point list. That is, for example, a method of signaling information on the layer dependency before information on the operation point list may be proposed.

Also, as an example, for each OLS, a method of signaling the entire list of layers included in the OLS may be proposed. It may not be necessary to signal information on layer dependency through the method of this embodiment.

Also, as an example, a flag indicating whether information on a maximum temporal sublayer required for inter-layer prediction for each layer of the OLS exists may be signaled. That is, for example, a method of signaling a flag indicating whether information on the maximum temporal sub-layer required for inter-layer prediction for each layer of the OLS exists may be proposed.

a) For example, the flag proposed in this embodiment may be called max_tid_il_present_flag.

b) Also, for example, when the max_tid_il_present_flag is 1, for each layer other than the output layer in the OLS, information on the maximum temporal sub-layer required for inter-layer prediction (ie, max_tid_il_ref_pics_plus1) may exist. That is, when the max_tid_il_present_flag is 1, information (ie, max_tid_il_ref_pics_plus1) on the maximum temporal sub-layer for a layer other than the output layer in the OLS may be signaled.

Also, as an example, the signaling proposed in the above-described embodiment(s) may be applied to both signaling of information on operating points in VvcOperatingPointsRecord and OperatingPointGroupBox. That is, for example, a method of applying the signaling of information proposed in the above-described embodiment(s) to both information on operating points in VvcOperatingPointsRecord and OperatingPointGroupBox may be proposed.

For example, as an embodiment proposed in this document, a VvcOperatingPointsRecord configured as shown in the following table, that is, an operation point information sample group may be proposed.

Referring to Table 7 described above, all_independent_layers_flag, each_layer_is_an_ols_flag, and ols_mode_idc may not be signaled in the operation point information sample group. That is, the operating point information sample group may not include all_independent_layers_flag, each_layer_is_an_ols_flag, and ols_mode_idc. In addition, referring to Table 7 above, the signaling of the layer dependency information may be moved to a position before the signaling of the operation point list. That is, for example, information on the layer dependency in the operation point information sample group may be signaled before information on the operation point list. Specifically, for example, syntax elements max_layer_count, layerID, num_direct_ref_layers, direct_ref_layerID and/or max_tid_il_ref_pics_plus1 in the operating point information sample group may be signaled/parsed prior to syntax elements num_operating_points, output_layer_set_idx, ptl_idx and/or max_temporal.

In addition, referring to Table 7 above, instead of signaling the layer list included in the OLS for the operation point and information indicating whether the layer included in the OLS is an output layer, the layer that is the output layer in the OLS for the operation point Only lists can be signaled. Specifically, for example, in the operation point information sample group, the existing syntax element layer_count may not be signaled/parsed, the syntax element output_layer_count may be signaled/parsed, and the syntax element is_outputlayer may not be signaled/parsed. The syntax element output_layer_count may indicate the number of output layers of the OLS having the same Id as output_layer_set_idx of the operation point.

Semantics of the syntax elements output_layer_count and layer_id of the operating point information sample group proposed in this embodiment may be as shown in the following table.

For example, referring to Table 8 above, the syntax element output_layer_count may indicate the number of output layers of the OLS having the same Id as output_layer_set_idx of the operation point as defined in ISO/IEC 23090-3.

Also, for example, referring to Table 8 above, the syntax element layer_id may provide a nuh_layer_id value for the output layer of the OLS having the same Id related to the operation point as output_layer_set_idx.

Also, for example, as another embodiment proposed in this document, a VvcOperatingPointsRecord configured as shown in the following table, that is, an operation point information sample group may be proposed.

Referring to Table 9 above, the operation point information sample group may include max_tid_il_present_flag. That is, for example, max_tid_il_present_flag may be signaled/parsed in the operation point information sample group. Here, max_tid_il_present_flag may be a flag indicating whether information on a maximum temporal sub-layer required for inter-layer prediction for each layer of the OLS exists as described above. That is, for example, max_tid_il_present_flag may indicate whether max_tid_il_ref_pics_plus1 for a corresponding layer exists.

In addition, referring to Table 9 above, when the target layer is not an output layer (that is, the value of is_outputlayer for the target layer is 0) and the value of max_tid_il_present_flag for the target layer is 1, the operation point information sample group In , max_tid_il_ref_pics_plus1 may be signaled/parsed. For example, max_tid_il_ref_pics_plus1 may indicate the maximum number of temporal sub-layers that can be used for inter-layer prediction for decoding a picture of another layer in the target layer as described above. For example, a value obtained by subtracting 1 from max_tid_il_ref_pics_plus1 may indicate the maximum number of temporal sublayers that can be used for interlayer prediction in a target layer.

Semantics of the syntax elements max_tid_il_present_flag and max_tid_il_ref_pics_plus1 of the operation point information sample group proposed in this embodiment may be as shown in the following table.

For example, referring to Table 10 above, the syntax element max_tid_il_present_flag may indicate whether the syntax element max_tid_il_ref_pics_plus1 exists. For example, max_tid_il_present_flag equal to 1 may indicate that the syntax element max_tid_il_ref_pics_plus1 may be present. Also, for example, max_tid_il_present_flag equal to 0 may indicate that the syntax element max_tid_il_ref_pics_plus1 does not exist.

Also, for example, referring to Table 10 above, the syntax element max_tid_il_ref_pics_plus1 may indicate the maximum number of temporal sub-layers that can be used for inter-layer prediction of pictures of other layers in the target layer. For example, max_tid_il_ref_pics_plus1 equal to 0 is not an IRAP picture, nor is a GDR picture having ph_recovery_poc_cnt equal to 0. A picture of a layer having the same layer Id as layer_id is an interlayer reference picture for decoding a picture of another layer in OLS (Interlayer reference picture) It may indicate that it is not used as a Layer Reference Picture (ILRP). Also, for example, max_tid_il_ref_pics_plus1 greater than 0 is not used as an ILRP for a picture of a layer with a TemporalId greater than max_tid_il_ref_pics_plus1 - 1 (that is, max_tid_il_ref_pics_plus1 minus 1) in order to decode a picture in another layer of the OLS. An APS having nuh_layer_id equal to layer_id and TemporalId greater than max_tid_il_ref_pics_plus1 - 1 (ie, max_tid_il_ref_pics_plus1 minus 1) may indicate that it is not referenced. Meanwhile, when the max_tid_il_ref_pics_plus1 does not exist, the value of max_tid_il_ref_pics_plus1 may be considered to be the same as max_temporal_id.

Referring to FIG. 4 , a first device may configure VvcOperatingPointsRecord (operation point information sample group) and/or OperatingPointGroupBox (operation point entity group) ( S400 ). For example, the first device may represent a transmission end, an encoding end, or a media file generating end. For example, the first device may acquire encoded image/video information through a network or a (digital) storage medium. Here, the network may include a broadcasting network and/or a communication network, and the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD. Also, the first device may include an encoder and derive the encoded image/video information. Then, the first device may configure VvcOperatingPointsRecord (operation point information sample group) and/or OperatingPointGroupBox (operation point entity group). For example, the first device may configure VvcOperatingPointsRecord and/or OperatingPointGroupBox for the encoded image/video information according to the above-described embodiment.

Thereafter, the first device may generate a media file based on the VvcOperatingPointsRecord and/or OperatingPointGroupBox ( S410 ).

The second device may obtain/receive a media file including VvcOperatingPointsRecord and/or OperatingPointGroupBox ( S500 ). For example, the second device may represent a reception end, a decoding end, or a rendering end.

For example, the media file may include the information described in Table 1, Table 3, Table 7, and/or Table 9. For example, the VvcOperatingPointsRecord and/or OperatingPointGroupBox may include information/fields of the embodiment(s) proposed in this document.

The second device may parse/obtain the VvcOperatingPointsRecord and/or OperatingPointGroupBox ( S510 ). The second device may parse/obtain the VvcOperatingPointsRecord and/or OperatingPointGroupBox included in the media file. For example, the VvcOperatingPointsRecord and/or OperatingPointGroupBox may include information related to an operating point (or information related to OLS), and the second device derives an operating point (or OLS) based on the VvcOperatingPointsRecord and/or OperatingPointGroupBox can do. Based on the derived operating point (or OLS), image/video decoding and/or (decoded) picture output may be performed.

6 schematically illustrates a method of generating a media file by a media file generating apparatus according to the present document. The method disclosed in FIG. 6 may be performed by the apparatus for generating a media file disclosed in FIG. 7 . The media file generating device may represent the above-described first device. Specifically, for example, steps S600 to S620 of FIG. 6 may be performed by the image processing unit of the media file generating apparatus, and S630 may be performed by the media file generating unit of the media file generating apparatus. Also, although not shown, the process of encoding the bitstream including image information may be performed by the encoder of the media file generating apparatus.

The media file generating apparatus configures first flag information for a target layer in an output layer set (OLS) ( S600 ). The first flag information may indicate whether information on the maximum number of temporal sub-layers for inter-layer prediction exists.

For example, the apparatus for generating a media file may derive encoded image information, configure an operation point information sample group for a bitstream including the encoded image information, and include the operation point information sample group media files can be created. For example, the apparatus for generating a media file may derive encoded image information, and based on the encoded image information, whether information on the maximum number of temporal sub-layers for inter-layer prediction exists in relation to the target layer It may be determined whether or not there is, and the first flag information for the target layer may be configured based on a result of the determination. That is, for example, the apparatus for generating a media file may determine whether a temporal sub-layer that can be used for inter-layer prediction of a picture of another layer exists in the target layer, and based on the result of the determination, The first flag information indicating whether the information on the maximum number of the temporal sub-layers for layer prediction exists may be configured. Meanwhile, for example, the apparatus for generating a media file may acquire the encoded image information through a network or a (digital) storage medium. Here, the network may include a broadcasting network and/or a communication network, and the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD. Alternatively, for example, the apparatus for generating a media file may include an encoder, and may derive the encoded image information.

For example, the syntax element of the first flag information may be the above-described max_tid_il_present_flag. For example, the first flag information equal to 1 may indicate that the information about the maximum number of the temporal sub-layers may exist. Also, for example, the first flag information equal to 0 may indicate that the information about the maximum number of the temporal sub-layers does not exist.

The media file generating apparatus configures second flag information on whether the target layer is an output layer (S610). For example, the apparatus for generating a media file may derive encoded image information, determine whether the target layer is an output layer based on the encoded image information, and may determine whether the target layer is an output layer based on a result of the determination The second flag information regarding whether the layer is an output layer may be configured.

For example, the syntax element of the second flag information may be the is_outputlayer described above. For example, the second flag information equal to 1 may indicate that the target layer is the output layer. Also, for example, the second flag information equal to 0 may indicate that the target layer is not the output layer.

The media file generating apparatus configures the information on the maximum number of the temporal sub-layers based on the first flag information and the second flag information (S620). The apparatus for generating a media file may configure the information on the maximum number of the temporal sub-layers based on the first flag information and the second flag information. For example, when the first flag information indicates that the information on the maximum number of temporal sub-layers may exist, and the second flag information indicates that the target layer is not the output layer, a media file The generating device may configure the information on the maximum number of the temporal sub-layers in the operation point information sample group, wherein the first flag information does not include the information on the maximum number of the temporal sub-layers or when the second flag information indicates that the target layer is the output layer, the media file generating device may not configure the information about the maximum number of the temporal sub-layers in the operation point information sample group. there is. That is, for example, when the value of the first flag information is 1 and the value of the second flag information is 0, the media file generating apparatus includes the maximum number of the temporal sub-layers in the operation point information sample group. may configure the information for, and when the value of the first flag information is 0 or the value of the second flag information is 1, the media file generating apparatus stores the temporal sub-layer in the operation point information sample group. The above information for the maximum number may not be configured.

For example, the information about the maximum number of the temporal sub-layers may be configured in the operation point information sample group based on the first flag information equal to 1 and the second flag information equal to 0. That is, for example, when the value of the first flag information is 1 and the value of the second flag information is 0, the information about the maximum number of the temporal sub-layers is configured in the operation point information sample group can be Also, for example, the information about the maximum number of temporal sub-layers is not configured in the operation point information sample group based on the first flag information equal to 0 and/or the second flag information equal to 1 may not be That is, for example, when the value of the first flag information is 0 or the value of the second flag information is 1, the information about the maximum number of the temporal sub-layers is configured in the operation point information sample group it may not be

For example, the syntax element of the information for the maximum number of the temporal sub-layers may be the above-described max_tid_il_ref_pics_plus1. For example, a value obtained by subtracting 1 from the value of the information on the maximum number of temporal sub-layers may be derived as the maximum number of temporal sub-layers.

Specifically, for example, the information on the maximum number of temporal sub-layers may indicate the maximum number of temporal sub-layers required for inter-layer prediction of pictures of other layers in a target layer. For example, a value obtained by subtracting 1 from the value of the information on the maximum number of temporal sublayers may indicate the maximum number of temporal sublayers required for interlayer prediction in a target layer. In addition, for example, the information about the maximum number of the temporal sub-layers equal to 0 is not an Intra Random Access Point (IRAP) picture and a Gradual Decoding Refresh (GDR) picture with ph_recovery_poc_cnt equal to 0. It may indicate that the picture is not used as an Inter Layer Reference Picture (ILRP) for decoding a picture of another layer in the OLS. Here, ILRP may indicate a reference picture used for inter-layer prediction. Also, for example, the information about the maximum number of temporal sub-layers greater than 0 is 1 in the value of the information about the maximum number of temporal sub-layers to decode a picture in another layer of OLS. A picture of the target layer with TemporalId greater than the subtracted value is not used as ILRP, nuh_layer_id is the same as layer_id and TemporalId is greater than the value of information about the maximum number of temporal sublayers minus 1 may indicate that it is not. Meanwhile, when the information on the maximum number of temporal sub-layers does not exist, the value of the information on the maximum number of temporal sub-layers may be regarded as equal to max_temporal_id.

The media file generating apparatus generates a media file including the operation point information sample group (S630). The media file generating apparatus may generate a media file including the operation point information sample group. Meanwhile, for example, the operation point information sample group may be called VvcOperatingPointsRecord.

For example, the operation point information sample group may include the first flag information and the second flag information. Also, for example, the information about the maximum number of the temporal sub-layers may be configured in the operation point information sample group based on the first flag information equal to 1 and the second flag information equal to 0. . That is, for example, when the value of the first flag information is 1 and the value of the second flag information is 0, the information about the maximum number of the temporal sub-layers is configured in the operation point information sample group can be

Meanwhile, for example, the operation point information sample group may include information on layer dependency and information on a list of operation points. For example, the information on the layer dependency in the operation point information sample group may be signaled before the information on the list of operation points. That is, for example, the information on the layer dependency and the information on the list of the operation points may be configured in the operation point information sample group, and the layer dependency in the operation point information sample group may be configured. The information on can be constructed prior to the information about the list of actuation points.

For example, the information on the layer dependency includes information indicating the number of all (unique) layers of all operation points, layer ID information, information on the number of direct reference layers, and/or direct reference layer ID information may include The syntax element of the information indicating the number of layers of the operation points is max_layer_count as described above, the syntax element of the layer ID information is layerID, the syntax element of the information on the number of the direct reference layers is the above-described num_direct_ref_layers, and the direct reference layer The syntax element of ID information may be the above-described direct_ref_layerID.

Also, for example, the information on the list of actuation points may include information on the number of actuation points, OLS index information for the actuation points, PTL structure index information for OLS and/or maximum temporal ID information. may include For example, the information on the number of operation points may indicate the number of operation points, the OLS index information may indicate an OLS for the operation points, and the PTL structure index information may indicate the number of operation points for the OLS. It may indicate a PTL structure, and the maximum temporal ID information may indicate a maximum temporal ID (TemporalId) of a NAL unit of operation points. The syntax element of the information on the number of operating points is the above-described num_operating_points, the syntax element of the OLS index is output_layer_set_idx, the syntax element of the PTL structure index information is the above-described ptl_idx, and the syntax element of the maximum temporal ID information is the above-described max_temporal_id can be

Alternatively, for example, the operation point information sample group may include information on a list of output layers in the OLS, and may not include information on a list of layers other than an output layer in the OLS. That is, for example, information on a list of output layers in the OLS may be configured/included in the operation point information sample group, and information on a list of layers other than an output layer in the OLS may be configured/not included. there is. In this case, the above-described second flag information may not be configured/included in the operation point information sample group. For example, the information on the list of output layers may include information on the number of output layers and/or layer ID information. For example, the information on the number of output layers may indicate the number of output layers in the OLS, and the layer ID information may indicate a layer ID of a layer with respect to the layer ID information. The syntax element of the information on the number of output layers may be the above-described output_layer_count, and the syntax element of the layer ID information may be the above-described layer_id.

Alternatively, for example, the operation point information sample group may include information on the entire list of layers in the OLS, but may not include information on the layer dependency. That is, for example, information on the entire list of layers in the OLS may be configured/included in the operation point information sample group, and information on the layer dependency may not be configured/included.

Or, for example, the operation point information sample group includes flag information on whether all layers are independently coded without using inter-layer prediction, and whether each Output Layer Set (OLS) includes only one output layer. Flag information and/or OLS mode index information indicating the mode of each OLS may not be included. That is, for example, flag information on whether all layers in the operation point information sample group are independently coded without using inter-layer prediction, and whether each Output Layer Set (OLS) includes only one output layer. Flag information and/or OLS mode index information indicating the mode of each OLS may be configured/not included. For example, the syntax element of the flag information for whether all the layers are independently coded without using inter-layer prediction is the above-described all_independent_layers_flag, whether each Output Layer Set (OLS) includes only one output layer. The syntax element of the flag information for the . . may be each_layer_is_an_ols_flag, and the syntax element of the OLS mode index information indicating the mode of each OLS may be ols_mode_idc.

Meanwhile, although not shown, the media file generating apparatus may store the generated media file in a (digital) storage medium or transmit it to the media file processing apparatus through a network or a (digital) storage medium. Here, the network may include a broadcasting network and/or a communication network, and the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD.

7 schematically shows a media file generating apparatus that performs the media file generating method according to the present document. The method disclosed in FIG. 6 may be performed by the apparatus for generating a media file disclosed in FIG. 7 . Specifically, for example, the image processing unit of the apparatus for generating a media file of FIG. 7 may perform operations S600 to S620 , and the media file generation unit of the apparatus for generating a media file of FIG. 7 may perform operations S630 . Also, although not shown, the process of encoding the bitstream including image information may be performed by the encoder of the media file generating apparatus.

8 schematically illustrates a media file processing method by a media file processing apparatus according to the present document. The method disclosed in FIG. 8 may be performed by the apparatus for processing a media file illustrated in FIG. 9 . The media file processing device may represent the above-described second device. Specifically, for example, S800 of FIG. 8 may be performed by the receiving unit of the media file processing apparatus, and S810 may be performed by the media file processing unit of the media file processing apparatus. Also, although not shown, the process of decoding the bitstream based on the decoder configuration record may be performed by the decoder of the media file processing apparatus.

The media file processing apparatus acquires a media file including the operation point information sample group (S800). For example, the media file processing apparatus may acquire the media file including the operation point information sample group through a network or a (digital) storage medium. Here, the network may include a broadcasting network and/or a communication network, and the digital storage medium may include various storage media such as USB, SD, CD, DVD, Blu-ray, HDD, and SSD.

The media file processing apparatus parses the operation point information sample group (S810). For example, the media file processing apparatus may parse/derive the operation point information sample group.

Specifically, for example, the media file processing apparatus may parse first flag information for a target layer in an output layer set (OLS). That is, the media file processing apparatus may parse the first flag information included in the operation point information sample group. The first flag information may indicate whether information on the maximum number of temporal sub-layers for inter-layer prediction exists.

Also, for example, the media file processing apparatus may parse second flag information regarding whether the target layer is an output layer. That is, the media file processing apparatus may parse the second flag information included in the operation point information sample group. The second flag information may indicate whether the target layer is the output layer.

Also, for example, the media file processing apparatus may parse the information about the maximum number of the temporal sub-layers based on the first flag information and the second flag information.

For example, when the first flag information indicates that the information on the maximum number of temporal sub-layers may exist, and the second flag information indicates that the target layer is not the output layer, a media file the processing device may parse the information on the maximum number of the temporal sub-layers in the operation point information sample group, wherein the first flag information does not include the information on the maximum number of the temporal sub-layers or when the second flag information indicates that the target layer is the output layer, the media file processing apparatus may not parse the information about the maximum number of the temporal sub-layers in the operation point information sample group. there is. That is, for example, when the value of the first flag information is 1 and the value of the second flag information is 0, the media file processing apparatus is the maximum number of the temporal sub-layers in the operation point information sample group. can parse the information for, and when the value of the first flag information is 0 or the value of the second flag information is 1, the media file processing apparatus determines the temporal sub-layer in the operation point information sample group. The above information for the maximum number may not be parsed.

For example, the information about the maximum number of the temporal sub-layers may be configured/included in the operation point information sample group based on the first flag information equal to 1 and the second flag information equal to 0. That is, for example, when the value of the first flag information is 1 and the value of the second flag information is 0, the information about the maximum number of the temporal sub-layers is configured in the operation point information sample group /may be included. Also, for example, the information about the maximum number of temporal sub-layers is configured in the operation point information sample group based on the first flag information equal to 0 and/or the second flag information equal to 1 may not be included. That is, for example, when the value of the first flag information is 0 or the value of the second flag information is 1, the information about the maximum number of the temporal sub-layers is configured in the operation point information sample group /may not be included.

Meanwhile, for example, the operation point information sample group may include information on layer dependency and information on a list of operation points. For example, in the operation point information sample group, the information on the layer dependency may be signaled/parsed before the information on the list of operation points. That is, for example, the information on the layer dependency and the information on the list of the operation points may be configured/included in the operation point information sample group, and the layer dependency in the operation point information sample group The information about time may be configured/included before the information about the list of actuation points.

Meanwhile, although not shown, the media file processing apparatus may decode the bitstream based on the decoder configuration record. For example, the media file processing apparatus may decode image information in the bitstream for the operation point information sample group based on information included in the operation point information sample group, and select a reconstructed picture based on the image information can create

9 schematically shows a media file processing apparatus performing a media file processing method according to the present document. The method disclosed in FIG. 8 may be performed by the apparatus for processing a media file illustrated in FIG. 9 . Specifically, for example, the receiving unit of the media file processing apparatus of FIG. 9 may perform S800 of FIG. 8 , and the media file processing unit of the media file processing apparatus of FIG. 9 may perform S810 of FIG. 8 . Meanwhile, although not shown, the media file processing apparatus may include a decoder, and the decoder may decode a bitstream based on the operation point information sample group.

According to this document described above, since the value of information indicating the maximum number of temporal layers for intra-layer inter-layer prediction may be different depending on the OLS to which the layer belongs, flag information indicating whether the information is signaled and the layer are output It may be determined in consideration of whether the layer is a layer, thereby reducing signaling redundancy for media file delivery and improving overall coding efficiency.

In addition, according to this document, signaling of information on layer dependency can be performed like the methods proposed in various embodiments, thereby reducing signaling redundancy for media file delivery and overall coding efficiency can improve

In the above embodiment, the methods are described on the basis of a flowchart as a series of steps or blocks, but this document is not limited to the order of the steps, and some steps may occur in a different order or concurrently with other steps as described above. there is. In addition, those skilled in the art will understand that the steps shown in the flowchart are not exhaustive and that other steps may be included or that one or more steps of the flowchart may be deleted without affecting the scope of this document.

Embodiments described in this document may be implemented and performed on a processor, microprocessor, controller, or chip. For example, the functional units shown in each figure may be implemented and performed on a computer, a processor, a microprocessor, a controller, or a chip. In this case, information for implementation (ex. information on instructions) or an algorithm may be stored in a digital storage medium.

In addition, devices to which embodiments of this document are applied are multimedia broadcasting transceivers, mobile communication terminals, home cinema video devices, digital cinema video devices, surveillance cameras, video conversation devices, real-time communication devices such as video communication devices, and mobile streaming devices. , storage medium, camcorder, video on demand (VoD) service providing device, OTT video (Over the top video) device, internet streaming service providing device, three-dimensional (3D) video device, videophone video device, transportation terminal (ex. It may be included in a vehicle terminal, an airplane terminal, a ship terminal, etc.) and a medical video device, and may be used to process a video signal or a data signal. For example, the OTT video (Over the top video) device may include a game console, a Blu-ray player, an Internet-connected TV, a home theater system, a smart phone, a tablet PC, a digital video recorder (DVR), and the like.

In addition, the processing method to which the embodiments of this document are applied may be produced in the form of a program executed by a computer, and may be stored in a computer-readable recording medium. Multimedia data having a data structure according to this document may also be stored in a computer-readable recording medium. The computer-readable recording medium includes all types of storage devices and distributed storage devices in which computer-readable data is stored. The computer-readable recording medium includes, for example, Blu-ray Disc (BD), Universal Serial Bus (USB), ROM, PROM, EPROM, EEPROM, RAM, CD-ROM, magnetic tape, floppy disk and optical It may include a data storage device. In addition, the computer-readable recording medium includes a medium implemented in the form of a carrier wave (eg, transmission through the Internet). In addition, the bitstream generated by the encoding method may be stored in a computer-readable recording medium or transmitted through a wired/wireless communication network.

In addition, the embodiments of this document may be implemented as a computer program product using program codes, and the program codes may be executed in a computer according to the embodiments of this document. The program code may be stored on a carrier readable by a computer.

A content streaming system to which embodiments of this document are applied may largely include an encoding server, a streaming server, a web server, a media storage, a user device, and a multimedia input device.

The encoding server generates a bitstream by compressing content input from multimedia input devices such as a smart phone, a camera, a camcorder, etc. into digital data, and transmits it to the streaming server. As another example, when multimedia input devices such as a smartphone, a camera, a camcorder, etc. directly generate a bitstream, the encoding server may be omitted.

The bitstream may be generated by an encoding method or a bitstream generating method to which embodiments of this document are applied, and the streaming server may temporarily store the bitstream in the process of transmitting or receiving the bitstream.

The streaming server transmits multimedia data to the user device based on a user's request through the web server, and the web server serves as a medium informing the user of what kind of service is available. When a user requests a desired service from the web server, the web server transmits it to a streaming server, and the streaming server transmits multimedia data to the user. In this case, the content streaming system may include a separate control server. In this case, the control server serves to control commands/responses between devices in the content streaming system.

The streaming server may receive content from a media repository and/or an encoding server. For example, when content is received from the encoding server, the content may be received in real time. In this case, in order to provide a smooth streaming service, the streaming server may store the bitstream for a predetermined time.

Examples of the user device include a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation system, a slate PC, Tablet PC (tablet PC), ultrabook (ultrabook), wearable device (eg, watch-type terminal (smartwatch), glass-type terminal (smart glass), HMD (head mounted display)), digital TV, desktop There may be a computer, digital signage, and the like. Each server in the content streaming system may be operated as a distributed server, and in this case, data received from each server may be distributed and processed.

The claims described herein may be combined in various ways. For example, the technical features of the method claims of the present specification may be combined and implemented as an apparatus, and the technical features of the apparatus claims of the present specification may be combined and implemented as a method. In addition, the technical features of the method claim of the present specification and the technical features of the apparatus claim may be combined to be implemented as an apparatus, and the technical features of the method claim and the technical features of the apparatus claim of the present specification may be combined and implemented as a method.

Claims

A method for creating a media file, comprising:

configuring first flag information for a target layer in an output layer set (OLS), wherein the first flag information indicates whether information on the maximum number of temporal sub-layers for inter-layer prediction exists;

configuring second flag information on whether the target layer is an output layer;

constructing the information on the maximum number of the temporal sub-layers based on the first flag information and the second flag information; and

creating a media file comprising a group of actuation point information samples;

The operation point information sample group includes the first flag information and the second flag information,

The method of claim 1, wherein the information on the maximum number of temporal sub-layers is configured in the operation point information sample group based on the first flag information equal to 1 and the second flag information equal to 0. .
According to claim 1,

and a value obtained by subtracting 1 from the value of the information on the maximum number of temporal sub-layers is derived as the maximum number of temporal sub-layers.
According to claim 1,

The first flag information equal to 1 indicates that the information about the maximum number of the temporal sub-layers may exist,

The method of claim 1, wherein the first flag information equal to 0 indicates that the information on the maximum number of the temporal sub-layers does not exist.
4. The method of claim 3,

The second flag information equal to 1 indicates that the target layer is the output layer,

The second flag information equal to 0 indicates that the target layer is not the output layer.
According to claim 1,

The operation point information sample group includes information on layer dependency and information on a list of operation points,

The method according to claim 1, wherein the information on the layer dependency in the operation point information sample group is signaled before the information on the list of operation points.
According to claim 1,

The method of claim 1, wherein the operation point information sample group includes information on a list of output layers in the OLS.
7. The method of claim 6,

The method of claim 1, wherein the operation point information sample group does not include information on a list of layers other than the output layer in the OLS.
According to claim 1,

The method of claim 1, wherein the operation point information sample group includes information on a full list of layers in the OLS.
9. The method of claim 8,

The method for generating a media file, characterized in that the operation point information sample group does not include information on layer dependency.
According to claim 1,

The operation point information sample group includes flag information on whether all layers are independently coded without using inter-layer prediction, flag information on whether each output layer set (OLS) includes only one output layer, and each OLS A method of creating a media file, characterized in that it does not include OLS mode index information indicating the mode of .
A media file generating apparatus, comprising: generating a media file by performing the method of claim 1 .
In the media file processing method,

acquiring a media file including a working point information sample group; and

parsing the actuation point information sample group,

Parsing the operation point information sample group comprises:

Parsing first flag information for a target layer in an output layer set (OLS), wherein the first flag information indicates whether information on the maximum number of temporal sub-layers for inter-layer prediction exists;

parsing second flag information on whether the target layer is an output layer; and

Parsing the information on the maximum number of the temporal sub-layers based on the first flag information and the second flag information,

The operation point information sample group includes the first flag information and the second flag information,

The information on the maximum number of temporal sub-layers is configured in the operation point information sample group based on the first flag information equal to 1 and the second flag information equal to 0. .
13. The method of claim 12,

and a value obtained by subtracting 1 from the value of the information on the maximum number of temporal sub-layers is derived as the maximum number of temporal sub-layers.
13. The method of claim 12,

The first flag information equal to 1 indicates that the information about the maximum number of the temporal sub-layers may exist,

The method of claim 1, wherein the first flag information equal to 0 indicates that the information on the maximum number of the temporal sub-layers does not exist.
15. The method of claim 14,

The second flag information equal to 1 indicates that the target layer is the output layer,

The second flag information equal to 0 indicates that the target layer is not the output layer.
13. The method of claim 12,

The method according to claim 1, wherein the operation point information sample group includes information about the entire list of layers in the OLS.
A media file processing apparatus, which processes a media file by performing the media file processing method of claim 12 .